The sewing of various components of a mattress together to form a finished product presents several sewing challenges. One such challenge is the sewing of the components at their respective corners. For example, pillow-top mattresses are constructed to appear as though a comforter or pillow has been placed on a conventional mattress to provide a more luxurious and comfortable appearance. The pillow-top is connected to the upper decking of the mattress by an intermediate gusset of folded material. Several different techniques are known to sew the edge of the pillow-top corners to corresponding corners of gusset so that the resulting sewn corners have a consistent and pleasing appearance. However, many of those techniques require various manual operations, and therefore, incorporating the gusset into pillow-top mattresses normally makes them more expensive to manufacture than conventional mattresses.
It is known to miter the gusset to form the gusset around a corner. With one system, the operator cuts an extended length of previously formed gusset material at measured locations where the corners of the cover are expected to be; and the mitered corner is formed on the gusset material before it is attached to the panel. However, due to the nature and construction of the mattress cover material and of the gusset material, often the gussets and panels shrink or change shape at different rates if left to sit, thus somewhat altering the location of the pre-mitered corner on the gusset material with respect to the corner on the mattress panel. This change occurs more frequently when the gusset is manufactured well in advance of the date of assembly of the mattress cover. Since the mitered corners on the gusset are not aligned precisely with the corners of the mattress cover panel, an accommodation has to be made by the operator at the time the gusset is attached to the mattress cover panel, such as by gathering the material or stretching where necessary to properly position the mitered corner. This adjustment results in extra operator time, as well as the possibility that the mitered corner is not properly positioned, or that the corner exhibits an uneven or undesired appearance. Even where the operator is able to properly position the mitered corner, the required stretching or gathering of the material produces a mattress cover which does not have the desired look and which night not be acceptable to all purchasers.
With another known system, a single machine is provided for making the gusset and for attaching the flange material. This machine folds the gusset, stitches it together in its folded condition, and secures the flange material to the gusset. The finished gusset is then cut into lengths and bound to a mattress panel. In conjunction with that operation, a mitering station is provided closely adjacent the binding machine. When it is desired to miter a corner of the gusset, as the operator approaches a corner of the mattress cover panel, the binding machine is stopped, and the operator measures exactly the distance from that point to the corner of the panel. An equivalent distance is marked on the gusset material. The operator then pulls that part of the gusset material over to the closely adjacent mitering station. The gusset material is first folded transversely at that point. Next, two stitches are applied by a sewing machine to the gusset from the folded edge inwardly. Each stitch is at a 45 degree angle with respect to the folded edge of the gusset, so that the stitches form a 90 degree angle with respect to each other. The sewing machine preferably is preprogrammed to stitch precisely the desired number of stitches needed for the miter. All the operator must do is wait until the stitches have completed, rotate the gusset material through 90 degrees and start the machine again. Thereafter, the triangular section defined by the stitches and the folded edge is cut out of the gusset material either automatically, or manually, and the gusset material is removed from the mitering station. While more automated, the above operation still requires numerous steps by the operator to form a corner during the process of attaching the gusset to another piece.
U.S. Pat. No. 6,834,603 discloses a system used to attach a gusset of an upper deck of a mattress like the one shown in U.S. Pat. No. 6,574,815. However, in such a mattress the ruffled gusset must be attached to the border panel, the pillow-top and lastly to the upper deck of the mattress. These multiple sewing steps are time consuming, increase the chance of operator error and increase the cost of the resulting product.
Therefore, there is a need for an improved process for reliably manufacturing a pillow-top mattress and the apparatus to implement the process.